fix(deps): update proxy-addr to 2.0.8

[anurag629]

What does this change?

Dependabot alert #101 (critical, GHSA-jqcg-44mw-7w3h): proxy-addr before 2.0.8 can be fooled by an IPv4-mapped IPv6 address when it checks trusted proxy subnets. We only get it through express 5.2.1, which pnpm installs for packages/server because express is an optional peer dependency there (the Express adapter tests use it). The published @chatcops/server doesn't ship express or proxy-addr, so this only touches our dev and test setup, but it clears the alert.

2.0.8 has the same dependencies as 2.0.7 (forwarded 0.2.0, ipaddr.js 1.9.1), so the lockfile change is only the version and the integrity hash, four lines.

How I tested this

• pnpm install --frozen-lockfile accepts the lockfile and installs proxy-addr 2.0.8 under express.
• pnpm -r build, pnpm -r typecheck and pnpm test (261 tests) pass.

Checklist

• This PR targets dev
• Changeset added: not needed, no published package changes